Method of attaching teeth to an earth drilling tool

ABSTRACT

Method of fabricating a combination earth drilling tool, which is in the form of a step auger having a pilot bit attached thereto, comprising arranging a downwardly spiraling flight member to an elongated axial hub member with the leading edge of the flight terminating in a plurality of cutting teeth disposed in a novel pattern relative to one another and to the flight. The cutting teeth are radially aligned respective to the hub and positioned along the leading edge of the flight member in a configuration which causes the innermost of the digging teeth to cut a first step outwardly from the pilot hole, while each of the remaining cutting teeth trail behind and cut subsequent steps into a formation. The pilot bit is in the form of a rotary bit and is fabricated by forming radially spaced pockets within a novel cylindrical member and a novel body portion so that the shank of a removable cutting tooth is received within the pocket with a portion of the shank extending outwardly of the pocket where the shank can be removably fastened to a shoulder formed between the body portion and the cylindrical portion. The pockets on both the flights and the rock bit are arranged into a configuration whereby any one of the cutting teeth can be substituted for any other one cutting tooth, thereby enabling a single type or designed cutting tooth to be utilized by both the step auger and the bit.

United States Patent 1 1 Taylor [451 Aug. 12, 1975 [76] Inventor: Thomas L. Taylor, 111 W. 10th St.,

Odessa, Tex. 79761 [22] Filed: Jan. 14, 1974 [211' Appl. No.: 433,285

[521 US. Cl 76/102; 76/108 R; 175/391; 175/394; 175/413; 299/87 [51] Int. C13... 821K 5/02; E21B 9/22; E21C 13/00 [58] Field of Search 175/57, 391, 394, 413;

299/87; 76/102, 108 R, 108 A, 108 B [56] References Cited UNITED STATES PATENTS 1,198,690 9/1916 Barton 175/413 X 2,341,237 2 1944 Phipps 76/108 R 2,480,537 8/1949 Arps et al. 175/394 X 2,756,025 7/1956 Lay 175/413 X 2,780,439 2/1957 Kandle 175/394 X 2,815,192 12/1957 Parrish 175/413 X 2,890,860 6/1959 Smith 175/394 X 3,024,856 3/1962 Henning.... 175/391 3,207,242 9/1965 Miller 175/413 X 3,485,116 12/1969 Fender 76/102 3,794,129 2/1974 Taylor. 175/413 Primary Examiner-Harrison L. Hinson Attorney, Agent, or Firm-Marcus L. Bates [5 7] ABSTRACT Method of fabricating a combination earth drilling tool, which is in the form of a step auger having a pilot bit attached thereto, comprising arranging a downwardly spiraling flight member to an elongated axial hub member with the leading edge of the flight terminating in a plurality of cutting teeth disposed in a novel pattern relative to one another and to the flight. The cutting teeth are radially aligned respective to the hub and positioned along the leading edge of the flight member in a configuration which causes the innermost of the digging teeth to cut a first step outwardly from the pilot hole, while each of the remaining cutting teeth trail behind and cut subsequent steps into a formation.

The pilot bit is in the form of a rotary bit and is fabricated by forming radially spaced pockets within a novel cylindrical member and a novel body portion so that the shank of a removable cutting tooth is received within the pocket with a portion of the shank extending outwardly of the pocket where the shank can be removably fastened to a shoulder formed between the body portion and the cylindrical portion. The pockets on both the flights and the rock bit are arranged into a configuration whereby any one of the cutting teeth can be substituted for any other one cutting tooth, thereby enabling a single type or designed cutting tooth to be utilized by both the step auger and the bit.

6 Claims, 15 Drawing Figures PATENTED M181 21915 SHEET 1 I8 FIG I x A x a 23 it l l I PATENTED M181 2% 3,898,895

SHEET 3 FIG. l5

METHOD OF A'I'IACHING TEETH TO AN EARTH DRILLING TOOL BACKGROUND OF THE INVENTION In forming bore holes in rock, gypsum, and the like with an auger, it is desirable to provide the auger with a pilot bit so as to accelerate the speed of penetration through the formation. It is furthermore desirable to be able to replace the cutting teeth on both the auger and pilot bit with replacement being effected in the field.

Another desirable attribute of an auger of the above described type is the realization of a maximum rate of penetration for a finite amount of power delivered by a prime mover. It is further desirable that the walls of the bore hole formed by an auger be maintained in a smooth condition so as to prevent irregularities therein which can cause caving of material. Hence, the auger should have digging teeth of durable material with the teeth each being of a design and being disposed in a particular pattern to cause the power expended thereinto to cut away a maximum amount of formation at a minimum cost.

Another desirable attribute of augers of the above described type is that they be rugged in design, low in cost, and enjoy a long life so that a considerable length of time expires between major repairs.

SUMMARY OF THE INVENTION This invention relates to a digging method comprising the use of a special step-type auger combination. The invention comprises a method of fabricating a heavy duty step-type auger in combination with a rotary rock bit wherein the step-type auger comprises an axial hub member having a downwardly spiraling flight affixed thereto and terminating in a plurality of cutting teeth. The cutting teeth are individually housed within a special pocket with each pocket being aligned along a radius drawn from the central longitudinal axis of the hub, and with each adjacent pocket being arranged relative to one another, so that the digging teeth are spaced both circumferentially and vertically. This configuration provides a step auger wherein the pilot bit, together with the cutting teeth which forms the leading edge of the flight, simultaneously cut a bore hole having a bottom most surface in the form of a plurality of concentrically arranged cylinders which dimenish in diameter in a downward direction.

The rotary rock bit is attached to the lowermost end of the auger hub and includes a cylindrical member which enlarges into a body portion with vertically disposed pockets being formed therewithin. Each pocket extends through both the body portion and an outer marginal portion of the cylindrical member, thereby leaving a downwardly opening cavity within which the shank of a rock cutting or digging tooth is received. The shoulder formed between the cylindrical member and the body portion provides a surface against which a fastener means associated with the shank can bear to thereby maintain the cutting teeth affixed to the bit.

A primary object of this invention is the provision of a method of fabricating a step type rock auger for use in combination with a rotary rock bit.

Another object of the invention is to provide a method of digging bore holes by the provision of a step type rock auger having pockets formed on the leading edge of the flight thereof, with the pockets being arranged vertically relative to the borehole and disposed along a radius drawn from the axial center line of the longitudinal central axis of the assembly, and with the pockets being spaced apart both vertically, angularly, and circumferentially from one another.

A further object of this invention is to provide a method of fabricating an earth auger so that a plurality of removable cutting teeth are arranged relative to one another enabling a maximum rate of penetration for a specific power requirement to be attained.

A still further object of this invention is to provide a method for fabricating a combination auger and pilot bit having removable cutting teeth thereon which may be readily substituted one for the other.

Another and still further object is to provide a new method for forming a borehole by the provision of a rotary rock cutting bit having a plurality of cutting teeth captured to the bit in an improved manner.

These and various other objects and advantages of the invention will become readily apparent to those skilled in the art upon reading the following detailed description and claims and by referring to the accompanying drawings.

The aboveobjects are attained in accordance with the present invention by the provision of a combination of elements which are fabricated in a manner substantially as described in the above abstract and summary.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of a heavy duty step type auger having a rotary rock pilot bit attached to the lower end thereof, with some parts being cut away therefrom;

FIG. 2 is a broken, diagrammatical, bottom view of the auger disclosed in FIG. 1, with some parts being removed therefrom and other parts being broken away to conserve space;

FIG. 3 is a top plan view of the apparatus disclosed in FIG. 1;

FIG. 4 is an enlarged plan view of the bottom-side of part of the apparatus disclosed in the foregoing figures;

FIG. 5 is a part cross-sectional view taken along line 5--5 of FIG. 4, and further disclosing additional parts added thereto;

FIG. 6 is a top plan view of the apparatus disclosed in FIGS. 4 and 5;

FIG. 7 is a part diagrammatical, part schematical, fragmentary representation of the results of the use of the apparatus of FIG. 1 while penetrating a formation;

FIG. 8A is a reduced top plan view which discloses one of the steps involved during the fabrication of part of the apparatus used in FIG. 1;

FIG. 8B is a reduced side elevational view of part of the apparatus disclosed in FIG. 1;

FIG. 8C is a reduced hypothetical top plan view disclosing a constructional feature of part of the apparatus of FIG. 1;

FIG. 9 is an enlarged elevational view of the pilot bit disclosed in FIG. 1, with some parts being removed therefrom for simplicity;

FIG. 10 is a bottom view of the apparatus of FIG. 9 with some parts thereof being removed for clarity;

FIG. 1 l is a top plan view of the apparatus disclosed in FIG. 9;

FIG. 12 is a fragmentary, part cross sectional side view of FIG. 10, with some additional parts being included;

FIG. 13 is a fragmentary, part cross-sectional view, taken along line 13-13 of FIG. 9;

FIG. 14 is a fragmentary, part cross-sectional view, similar in some respects to FIG. 12, which discloses a cutting tooth which is used in conjunction with the present invention; and,

FIG. 15 is an enlarged side view of a cutting tooth.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The arrow at 15 in FIG. 1 generally discloses a combination step type rock auger and rotary bit made in accordance with the present invention. The auger includes a longitudinally extending tubular-like structure 16 which is in the form of a square hub portion 17 having a chuck 18 at the upper extremity thereof for connection to a prime mover (not shown) in a manner which is known to those skilled in the art.

The square hub telescopingly receives a cylindrical drill shaft 19 therein with the lower terminal end 20 of the shaft threadedly receiving a pilot bit 21 therein. The hub and shaft may be one integral part, if desired. A flight in the form of a spiral web, having an outermost diameter 22, is affixed to the hub and to the shaft to present a trailing edge 23 and a leading edge 24.

The leading edge of the flight is provided with or formed into a plurality of cutting teeth 25. The teeth individually are removably received within a pocket 26 in one of several manners known to those skilled in the art, and specifically as will be taught later on in this disclosure.

A dummy web, generally indicated by the arrow at numeral 27, is symmetrically arranged relative to the flight in the illustrated manner of FIG. 1. The dummy web is provided with pockets and teeth in the before described manner. While a dummy web is illustrated herein, it should be understood that the invention comprehends the fabrication of apparatus devoid of such a web.

Looking now to the part schematical, part diagrammatical illustration of FIG. 2, it will be seen that the pockets 26 are arranged in a particular novel configuration, with any one pocket of the flight being diametrically opposed to the similarly positioned or corresponding pocket located on the dummy web. The innermost pockets 26 and 126 are preferably attached to both the shaft and to the leading edge of the flight. Each opposed pocket is arranged withtheir longitudinally extending axis coinciding with a radial line drawn through the longitudinal central axis of the drill shaft. This relative disposition of the pocket is hereinafter referred to as the radial longitudinal axis of the pocket. Outermost pocket 226 is spaced circumferentially from the innermost pocket and spaced vertically above the innermost pocket an amount determined by the pitch of the flight. The intermediate pockets 26' are progressively spaced apart from one another both circumferentially and vertically so that the resultant profile of the teeth will engage a formation in an overlapping man ner. Numeral 31 indicates the vertical distance each pocket, or adjacent cutting tooth, is spaced apart from one another.

As seen illustrated in FIGS. 4, 5, and 6, each pocket is provided with a tapered slot 28 which receives a complimentary tapered tang 29 of the cutting teeth in a wedge-like manner, with the rear face or abuttment mean 45 of the cutting tooth being abuttingly received by the illustrated load carrying member 30.

As an example of the specific details of an l8 inch diameter auger made in accordance with this invention, the flight preferably is fabricated from /2 inch plate, with the plate being apertured as seen at 19, and provided with a out along the radius thereof, thereby providing adjacent end portions 23, 24'. The end portions are pried apart vertically by placing the plate member in a hydraulic press and mold, thereby forming a portion of the length of the flight illustrated in FIG. 1. As seen illustrated in FIG. 8C, the plate portion forming the lowermost portion of the flight is provided with a plurality of cutouts with each of the cutouts being placed so that when one of the before mentioned pockets is welded therein, the resultant pocket will lie with the radial longitudinal axis thereof disposed in the before recited manner, and in a position to dispose the cutting edge portion of the teeth received therein normal to a circle described during one revolution of the auger shaft.

In a 24 inch OD auger having a 5 inch OD shaft, and using five pockets 2 /2 inches in length, each of the five pockets were arranged adjacent to one another in the manner illustrated bythe three innermost pockets of FIG. 2. The radial spacing 231 of the pockets was maintained at 1% inches. This configuration provided a flight having a strong leading edge since each pocket is welded to the flight, and to an adjacent pocket. It will be noted that this configuration disposed the teeth or pocket circumferentially about the flight an amount less than Looking now to the details of FIGS. 9 15', the pilot bit generally illustrated at arrow 21 is provided with the usual threaded pin end 32, which can take on any one of several known forms. Shoulder 34 is formed between cylindrical member 33 and the threaded coupling an amount consistent with the design of the drill shaft. The lower body portion is in the form of an enlargement having three equally spaced apart radially outwardly extending portions 35. The lower body portion is stepped-off from the cylindrical member by the provision of the illustrated shoulder 36, which preferably is planar in form, although it could take on other configurations while remaining within the scope of this invention.

The lower face 37 of the bit is also planer in form, and preferably includes a maximum OD which terminates at the outermost edge portion of the load carrying member 38. The load carrying member is defined by edge portions 39, 40, 41, and includes a lowermost face 42.

As best seen in the illustration of FIGS. 10 and 11, the body portion includes three radially extending enlargements having a trailing edge 40 and a leading edge 43 which form adequate structure within which a pocket 44 is formed. The pocket downwardly opens with the entrance thereto being defined by lower face 37 of the bit. The tapered pocket extends through the body portion enlargements and into a major portion of the cylindrical member, with the pocket having a portion thereof upwardly opening through shoulder 36 and another portion thereof outwardly opening from the outer periphery of the side wall of the cylindrical member 33.

Edge portion 46 of the cylindrical member defines the length of the roof 47 of the pocket, thereby leaving wall surface 48 of the cylindrical member for transfering loads into the threaded pin end 32. Spaced apart diametrically opposed walls 49, 50 of the pocket are arranged so that an upper portion of the tang of the before mentioned cutting teeth can freely extend outwardly of the cylindrical body portion of the bit in the area generally illustrated by the arrow at numeral 51, and as best seen in the illustration of FIGS. 9, l2 and 14 (in conjunction with FIG. 13).

Those skilled in the art will now appreciate that the pockets of the drill bit are of a configuration to enable the cutting teeth used in conjunction with the auger of FIG. 1 to also be used in conjunction with the rotary rock bit of FIG. 9, thereby bringing about the advantage of being able to maintain an inventory of a single type cutting tooth in order to supply the demands of both the auger and the bit.

It will further be noted that the pockets of the bit are arranged spaced from one another and to the axial center line of the bit, with the innermost edge portion of the pocket lying adjacent to a line drawn radially from the axial center line of the bit.

The apparatus, while penetrating a formation, removes material therefrom in a step like manner, with the pilot bit providing the first penetration at 121 of FIG. 7, and with the innermost cutting tooth of the auger forming the lowermost and innermost step out 125, and with the outermost and uppermost cutting tooth forming the last cut 225, to thereby form a borehole having a diameter 222. The number of intermediate steps, or cuts, provided by a corresponding number of cutting teeth, will depend upon the pitch and OD of the flight. Preferably, three or more cutting teeth will be employed with the teeth being spaced radially apart an amount 231, and vertically an amount as seen at 31, depending upon the number and configuration of the teeth employed.

The cutting teeth of the apparatus are individually inserted into a pocket by carefully striking the butt end 45 opposite the carbide cutting tip so as to drive the wedge shaped tang into the corresponding and complementary wedge shaped pocket, with the butt end being forced against the load carrying member or 42. The tang is provided with a keeper, such as a cotter pin, to prevent loss of the tooth should it inadvertently become unwedged from its pocket. The tang can be provided with dual apertures if desired, the central aperture being for use in conjunction with the auger pocket and the off-set aperture being for use in conjunction with the rotary bit. A single offset aperture will suffice for both applications, if desired.

1 claim:

1. Method of attaching teeth to an earth drilling tool, having a flight intergrally attached to a central hub and a pilot bit affixed at the lower end thereof comprising the steps of:

attaching the flight to the hub so that a lower end thereof terminates adjacent the pilot bit;

forming a leading edge onto the flight by welding a plurality of spaced teeth receiving pockets therein which are arranged respective to one another so that when a cutting tooth is placed therein, a radial dimension thereof is disposed along a line drawn radially of the axial centerline of said hub, and a circumferential dimension thereof is disposed normal to said radially drawn line;

placing a first of said pockets adjacent to said hub, a last of said pockets adjacent to the outer periphery of said flight, and the remaining of said pockets at different radii relative to each other and to said first and last pockets; and further arranging each of said pockets at different vertical elevations along said flight;

forming said flight from a disk having a central aperture and a radial cut extending from said aperture to the outer peripheral edge thereof to form a leading edge and a trailing edge by forcing said edges apart, thereby forming at least a portion of said flight.

2. The method of claim 1, and further including the 5 steps of:

forming a tooth receiving pocket into the pilot bit which will receive one of said digging teeth therein so that similar cutting teeth may be arbitrarily used in any one of the before recited pockets.

3. The method of claim 1 and further including the steps of:

forming a tooth receiving pocket on said pilot bit to receive one of said digging teeth therein so that similar cutting teeth may be arbitrarily used in any one of the before recited pockets;

fonning a dummy web on said axial hub member, and arranging said dummy web in opposed relationship respective to said flight; and, forming teeth receiving pockets onto the leading edge portion of the dummy web.

4. Method of mounting digging teeth onto an earth boring auger which has a flight formed directly onto a central support hub with the flight having a leading edge and a trailing edge, comprising the steps of:

l. removing material from the marginal lower end of the flight so that a plurality of spaced cutouts are formed therein;

2. positioning said cutouts during the material removing operation of step l) with adjacent cutouts being located along progressively longer radii, and with the mean radial center line thereof lying parallel to a radius drawn perpendicular from the axial centerline of the hub so that the edge portions which define the width of each cutout lies tangential respective to concentric circles drawn about the axial centerline of the hub;

3. welding a plurality of spaced individual teeth receiving pockets to the flight within each of the areas defined by a cutout;

4. positioning each said pocket respective to the cutout while carrying out step (3) to cause the cutting edge of any digging tooth placed therein to lie along a line drawn perpendicular to the axial centerline of the hub.

5. The method of claim 4, and further including the steps of:

5. forming a dummy web onto said axial hub member, in opposed relationship respective to said flight, and forming teeth receiving pockets onto the leading edge portion of the dummy web in the same described manner of steps 2-4.

6. The method of claim 4 and further including the steps of:

connecting a pilot bit to said axial hub member;

forming a tooth receiving pocket onto said pilot bit for receiving one of said digging teeth therein so that similar cutting teeth may be arbitrarily used in any one of the before recited pockets.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. ,898,895 DATED August 12, 1975 lNVENTORtS) Thomas L. Taylor it is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Line 76 of the cover page of the Letters Patent:

Correct the Inventor's address to read --Post Office Box 60b8,

Odessa, Tex. 79760-- instead of ELll W. 10th St. Odessa, Tex.

Signed and Sealed this eleventh of May 1976 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN :lmsll'ng ()ffiu' ('ummissium'r nj'lau'nls uml Trudomurkx 

1. Method of attaching teeth to an earth drilling tool, having a flight intergrally attached to a central hub and a pilot bit affixed at the lower end thereof comprising the steps of: attaching the flight to the hub so that a lower end thereof terminates adjacent the pilot bit; forming a leading edge onto the flight by welding a plurality of spaced teeth receiving pockets therein which are arranged respective to one another so that when a cutting tooth is placed therein, a radial dimension thereof is disposed along a line drawn radially of the axial centerline of said hub, and a circumferential dimension thereof is disposed normal to said radially drawn line; placing a first of said pockets adjacent to said hub, a last of said pockets adjacent to the outer periphery of said flight, and the remaining of said pockets at different radii relative to each other and to said first and last pockets; and further arranging each of said pockets at different vertical elevations along said flight; forming said flight from a disk having a central aperture and a radial cut extending from said aperture to the outer peripheral edge thereof to form a leading edge and a trailing edge by forcing said edges apart, thereby forming at least a portion of said flight.
 2. positioning said cutouts during the material removing operation of step (1) with adjacent cutouts being located along progressively longer radii, and with the mean radial center line thereof lying parallel to a radius drawn perpendicular from the axial centerline of the hub so that the edge portions which define the width of each cutout lies tangential respective to concentric circles drawn about the axial centerline of the hub;
 2. The method of claim 1, and further including the steps of: forming a tooth receiving pocket into the pilot bit which will receive one of said digging teeth therein so that similar cutting teeth may be arbitrarily used in any one of the before recited pockets.
 3. The method of claim 1 and further including the steps of: forming a tooth receiving pocket on said pilot bit to receive one of said digging teeth therein so that similar cutting teeth may be arbitrarily used in any one of the before recited pockets; forming a dummy web on said axial hub member, and arranging said dummy web in opposed relationship respective to said flight; and, forming teeth receiving pOckets onto the leading edge portion of the dummy web.
 3. welding a plurality of spaced individual teeth receiving pockets to the flight within each of the areas defined by a cutout;
 4. positioning each said pocket respective to the cutout while carrying out step (3) to cause the cutting edge of any digging tooth placed therein to lie along a line drawn perpendicular to the axial centerline of the hub.
 4. Method of mounting digging teeth onto an earth boring auger which has a flight formed directly onto a central support hub with the flight having a leading edge and a trailing edge, comprising the steps of:
 5. The method of claim 4, and further including the steps of:
 5. forming a dummy web onto said axial hub member, in opposed relationship respective to said flight, and forming teeth receiving pockets onto the leading edge portion of the dummy web in the same described manner of steps 2-4.
 6. The method of claim 4 and further including the steps of: connecting a pilot bit to said axial hub member; forming a tooth receiving pocket onto said pilot bit for receiving one of said digging teeth therein so that similar cutting teeth may be arbitrarily used in any one of the before recited pockets. 